First i started out with about a 2 inch hole in my lid. Now i have about a third left of the whole lid. Does this actually add anything horsepower wise, or is it just a harsh punishment to the filter that keeps your engine and carbs clean ?

 

That depends on if you bought the Dynojet kit. If you didn't, then your motor makes little if any more HP. Now it's running leaner than when you took delivery, and Yamaha sets them up lean to begin with. If you did install the Dynojet kit, you will notice the pickup immediately, because you added about 10% to the overall HP. If I were you, I would pickup a good aftermarket air filter, preferrably a ProDesign setup, to go with your new jet kit. www.rockymountainatv.com has the jet kit (listed as a K&N Stage 2 jet kit) and a selection of air filters. You can also go to www.dynojet.com to check out the info on the jet kit. I run the ProDesign/K&N/Outerwear/jet kit on mine and am extremely happy with the results, even without cutting the airbox lid and running the stock pipe. It pulls harder across the entire range and has a sharper response due to new slide springs included with the jet kit.

 

The above post is correct about the engine running lean...But you can fix that with larger jets. And You do not need a dyno jet kit to produce power. A properly jetted engine will accomplish the same thing.
If you are running without a cover...then get yourself an outerwear at the bare minimum. A pro design filter setup will help ensure that nothing gets into the carbs or engine.
A true Ten percent gain in HP would be hard to accomplish with jetting alone.

 

I do have the stage 2 dynojet kit, 148,150 mains, and a big gun full exhaust system. The slide springs... are they the small springs or the real big springs ? cuz i lost both of dyno's small springs somewhere out in my yard, had to put stock back in.

 

Dynojet Kits are for morons that have money to burn can't figure out their jetting them selves!

 

go to hell

 

Some people are just cheap... The DynoJet kit is the way to go. They help save you time and effort figuring out the jetting plus the needles are slightly thinner which lets them flow more fuel in the midrange. Dynojet does jetting for a living. They make these kits exclusively for each make and model to extract the most power. Definately worth it in my opinion. Whats 60$ when you just spent 6500$?!?!?!

 

Kiss my A$$ YfM 660r real men ride Banshees anyways moron. [img]i/expressions/face-icon-small-mad.gif[/img]

 

your banshee can't hang with this